Question

IMENTAL PROCEDURES AND DATA it A Micropipetting 2 The student has used a micropipette to add five 250 ml aliquos to: braker and recorded the masses below. 3) Determine the mass of EACH individual sample through subtraction) 4) Calculate the mean, standard deviation, and RSD for the mass of water. Mass of clean, dry beaker = 91.4536 Sample 1 2 3 Total Mass 91.7025 91.962 92.2168 92.454g 92.704 g Sample Mass .249g .5099 1.509 9 1.001 q 1. 2519 4 5 Calculations SHOW YOUR WORK. SD SE 2(x - F) n-1 % RSD = x 100 mean 1) Find the average mass of your samples. Are they close to 0.250 g each? If not propose why. The first sample was close =.9038 to .250g, as the total mass increased so did the sample. 2) Calculate standard deviation. 3) Calculate %RSD.

Answer 1

=0.9038 1 ) Average mass 2 2) So= {\H- x) •249-0.9038) + (-509-0.9038) + (1.509-0.9038) + (1-001-0.9038) + (1-251-6.9038) n-1 5-1 T .42876 + 6.15587 + 0.36626+0.00944 +-12054 4 10:2762175 = 0.5199 = 0.520 % RSD = x 100 = SD mean 0.520 Xloo - 57.5%. 0.9038